Option variable
taylor_logexpandDefault value: true
taylor_logexpand controls expansions of logarithms in
taylor series.
When taylor_logexpand is true, all logarithms are expanded fully so that
zero-recognition problems involving logarithmic identities do not
disturb the expansion process. However, this scheme is not always
mathematically correct since it ignores branch information.
When taylor_logexpand is set to false, then the only expansion of logarithms
that occur is that necessary to obtain a formal power series.